The Program for the International Assessment of Adult Competencies surveyed 166,000 teens and adults ranging in age from 16 to 65 years old in 24 countries.

In each of the main areas, adults in more than a dozen countries, including Japan, Finland, Australia and Canada, consistently scored higher than the United States, which ranked below average or near the bottom in almost every category.

Respondents were tested in basic reading and math as well as "activities such as calculating mileage reimbursement due to a salesman, sorting email and comparing food expiration dates on grocery store tags," according to The Associated Press.

Among the 22 OECD-affiiated countries participating in the study, the United States ranked below average in literacy proficiency — well below such countries as Japan and Finland, but still higher than France, Spain and Italy.

In numeracy proficiency — defined as "the ability to access, use, interpret and communicate mathematical information and ideas" — the United States ranked third from the bottom with a mean score of 253, just below France at 254. Japan's top mean score was 288 and Finland's 282. Spain scored at the bottom, with 246.

Sweden and Finland score highest in the category of problem-solving using computers; Spain, Italy and France trailed behind, with the U.S. scoring below average.

The AP says:

"Not only did Americans score poorly compared to many international competitors, the findings reinforced just how large the gap is between the nation's high- and low-skilled workers and how hard it is to move ahead when your parents haven't.

"In both reading and math, for example, those with college-educated parents did better than those whose parents did not complete high school."

Participating in the study were OECD member nations Australia, Austria, Belgium (Flanders), Canada, the Czech Republic, Denmark, Estonia, Finland, France, Germany, Ireland, Italy, Japan, Korea, the Netherlands, Norway, Poland, the Slovak Republic, Spain, Sweden, the United Kingdom (England and Northern Ireland), and the United States; and two partner countries, Cyprus and the Russian Federation.